A number of haptic user input devices have been developed to provide force feedback in response to a signal from a host computer, e.g., during simulations or game play executed on the host computer. For example, Microsoft Corporation's SIDEWINDER™ joystick provides haptic feedback to a user gripping the joystick in response to events occurring in computer games, based upon commands transmitted from a host computer to the joystick. For instance, if a simulated character displayed during execution of a computer game is struck by a simulated projectile, such as a boulder, a signal from the host computer causes an actuator in the joystick housing to abruptly move the joystick in the same direction as the path of the simulated projectile. The force produced by the actuator on the control handle imparts a haptic sensation to the user's hand, which is gripping the joystick control handle, indicating that the character has been hit by the projectile. In another instance, if a user commands a simulated character to move into a simulated wall, by moving the joystick control handle in an appropriate direction, a signal from the host computer causes the actuator to produce a force that resists the user's movement of the joystick control hand in that direction. This force imparts a haptic sensation to the user's hand that is gripping the joystick to indicate that the simulated character controlled by the joystick has run into the wall.
Similarly, Microsoft Corporation's SIDEWINDER™ wheel provides haptic feedback to a user gripping the wheel and using it to control a simulated vehicle, in response to a signal from the host computer on which the vehicle simulation is executed. If a simulated vehicle strikes and rebounds from a simulated wall, a signal from the simulation causes an actuator coupled to a shaft on which the wheel is mounted to abruptly turn the wheel in the same direction as the simulated vehicle is rebounding. The wheel also vibrates in response to a simulated rough surface over which the vehicle is traveling.
In contrast to haptic joysticks and haptic wheels, force feedback is typically applied to gamepad input devices in a different manner. A gamepad input device uses a multi-position rocker switch that is normally actuated by a user's thumb to provide input signals that control objects on a screen of a host computer or computing device. Since a gamepad input device does not include a control handle or wheel that is gripped by a user, haptic feedback cannot be applied directly to a control component that is held by the user. Instead, in prior art haptic gamepad input devices, a vibration that is applied to the housing of the gamepad has been produced in response to a signal from the host computing device. Vibration of the housing of a gamepad user input device is often produced by rotating offset counter weights or by energizing and de-energizing an electromagnetic device to vibrate a ferromagnetic mass. Such vibration does not provide a directional force feedback along a specific axis. Directionless vibration is thus currently used for several gamepad hand-held devices that do not include a joystick control handle, a wheel, or other control member that can be gripped and moved relative to the housing of the device. The relatively simple mechanisms that provide vibration do not add substantial weight to a gamepad, making it more comfortable for the user to support.
However, it would be desirable to enhance a user's experience with a hand-held input device such as a gamepad by providing directional haptic feedback to the user. One approach was disclosed in commonly assigned U.S. Pat. No. 5,643,087, which describes a hand-held input device with a moveable member that cradles a thumb or other digit of the user's hand. The moveable member is thus comparable to a non-graspable mini joystick control handle, but provides more effective contact with the user by at least partially looping around the user's digit. The moveable member can be moved relative to two orthogonal axes and receives a haptic force directed along one or both of these orthogonal axes.
While the above approach is effective, the directional haptic feedback is primarily limited to a single digit of a user. It would therefore be desirable to provide directional haptic feedback to at least one of the user's hands, as is currently provided by grasping the control handle or wheel of haptic devices, but without requiring a large graspable control member on the input device.